Variable-pressure electric-current transformer.



No. 678,5la. Patented July :6, |901. c. J. m'rzEn.

VARIABLE PRESSURE ELECTRIC CURRENT TRANSFCRMER.

(A'ppcaiion Bled Hu. 11, 1901.) (No Model.)

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311 murat FFICFQ CONRAD J. RITZER, OF SOHENEOTADY, NEI/V YORK.

VARIABLE-PRESSURE ELECTRIC-CURRENT TRANSFORMER.

srnorrroarrolv forming part of Letters Patent No. 678,518, dated J'uly 16, 1901.

Application filed March ll, 1901. Serial No. 50.670. (No model.)

To all whom t may concern:

Be it Vknown that I, CONRAD J. RITZER, a citizen of the United States, residing at Schenectady, in the county of Schenectady and State of New York, have invented certain new and useful Improvements in Variable-Pressure Electric-Current Transformers; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it` accuracy, a maximum amount of amperagek secured at a low voltage, and a continuous operation insured withoutliability of heating. With this and other objects in View, which will appear as the nature of the invention is better disclosed, the invention consists of certain novel features of construction and combination of parts, which will be hereinafter more fully described,and particularly pointed out in the appended claim.

In the accompanying drawings, Figure lis a side elevation, with parts in section, of a current-transformer embodying my invention; and Fig. 2 is a top plan view of the same, a portion of the casing being broken away to disclose the interior parts.

Referring now more particularly to the drawings, the numeral 1 represents the base, and 2 the inclosing casing, of the transformer. In the casing is mounted a resistance coil or ring comprising a laminatedcore 3, formed of a series of soft-iron punchings properly bound together. Surrounding this core is a layer l of insulating material, and around said insulating material is wound the secondary winding 5, which is covered by a layer of insulation' 6. The secondary winding 7 is wound upon this outer layer of insulationl 6 and is preferably composed of astrip of copper the outer surface of which is ground and buffed to a true surface.

In the center of the core is fitted a block 8, of wood or other suitable material, which is provided with a central socket, in which is fitted a conducting-bushing 9. This block is preferably made wedge-shaped to fit snugly down within the opening of the core. In the bushing 9 is rotatably fitted the reduced lower end of a shaft 10,which is threaded to receive a securing-nut ll and lock-nut 12. Between the nut l1 and the lower-'end of the bushing 9 is arranged a washer 13, which holds the parts in proper engagement, and by adjusting the nuts the shaft 1() may be adjusted to turn as freely as desired. The upper end of the shaft is provided with a socket, in which is iitted and secured by set-screws 14. the lower end of a stem l5,which projects outwardly and upwardly through a non-conducting bushing 16 in the top of the casing to the exterior and is provided with a handle 17, by which the shaft is adapted to be turned. To the shaft 10 is iixed'the inner end of a bracketarm 18, which carries at its outer end a sliding contact 19, which is adapted to move over the exposed faces or convolutions of the secondary coil or winding, soas to cut in or out any section of said coil or winding to increase or decrease the pressure of the current at the secondary terminals. A stop 2O is mounted upon the block S at the neutral -point and limits the movement of the contact 19, and the block 8 is preferably formed so as to secure free ventilation to prevent heating of the transformer in use.

2l indicates the primary terminals, 22 the primary connection, and 23 the secondary ter minals.

24 represents the primary switch for controlling the supply of current.

By turning the handle 17 to cause the contact 19 to move from the stop 2O over the eX'- posed faces or convolutions of the secondary winding 7 any portion of said secondary coil or winding may be cut in or out of circuit and the resistance to the passage of the main current increased or diminished, so as to supply a consumption-current of any desired power or intensity, and the construction of the device is such that it is adapted to carry its full load without difficulty or failure in operation and without liability of heating.

The great advantage of the device lies in its simplicity of construction and the case whereby a regulated current of any desired pressure may be economically obtained and the current adjusted with absolute accuracy from the highest to the lowest degree and a large amount of am perage generated at a very low voltage.

From the foregoing description7 taken in connection with the accompanying drawings, the construction, mode of operation, and advantages of the invention will be readily understood, and it will be seen that it provides a simple, durable, and effective device which is economical in use and may be employed for a variety of uses in which a current of uniform or less pressure than that supplied by the main current is desired.

Vhile the preferred embodiment of the invention is as herein disclosed, it will of course be understood that changes in the form, proportion, and minor details of construction may be made within the scope of the invention without departing from the spirit or sacrificing any of the advantages thereof.

Having thus fully described my invention, what l claim as new, and desire to secure by Letters Patent, is-

In an electric-current transfo1'mer,the combination of an annular laminated core,a spiral primary winding insulated from the core, an outer secondary Winding consisting of an exposed continuous spirally-Wound strip of conducting material insulated from said primary winding and having the outer faces of its spiral coils or convolutions forming spaced contact-surfaces, a wedge-shaped ventilated block fitting within the opening of the core, primary and secondary terminals and conneet-ions, a primary switch for controlling the supply of the, current, an insulated bushing fitted in the block and having the primary connection connected thereto, a shaft having a socket, and a stem projecting through said bushing and rotatably mounted therein, a handle having astem detachably fitted in said socket, a bracket-arm connected to the shaft and extending laterally therefrom, and a contact carried by said arm and adapted to be moved over the said contact-faces of the seo ondary winding, substantially as described.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

CONRAD J. RITZER.

Witnesses:

ALEX. FENWIGK,

ANDREW T. G. WEM'PL'E. 

